Comparison of two commercially available ELISA antibody test kits for detection of human antibodies against Coxiella burnetii.

BACKGROUND

Q fever is a zoonosis caused by Coxiella burnetii. The disease is emerging in many parts of the world, likely in part due to increased awareness and the availability of better diagnostic tests. The clinical diagnosis of Q fever is difficult, and most confirmed cases rely on serology.

METHODS

This study compared the sensitivity, specificity, and performance of 2 commercial enzyme-linked immunosorbent assay (ELISA) kits, with a commercial microimmunofluorescence antibody test (IFA) used as reference.

RESULTS

One of the ELISA kits showed a higher sensitivity and a lower cross-reactivity than the other kit. Likewise, the same kit was superior when comparing the area under the receiver operating characteristic curves.

CONCLUSIONS

The results support the continued use of IFA as a primary serological test for Q fever; for large numbers of samples, an ELISA kit can be used as a screening tool, if followed by a confirmatory IFA test.